Compliance and Audit
To operate the market effectively, MOSL must adhere to several rules and regulations, as well as ensure that each trading party meets its obligations. All documentation can be found below - please note you will need to be logged in to view any external auditor documentation.
Trading Party Audits
Trading party audits are an important part of the market assurance activities undertaken by MOSL. This was reaffirmed by the industry in 2024, through the Market Performance Framework (MPF) reform programme, which made trading party audits a formal tool under the reformed framework.
Every trading party audit MOSL delivers has been endorsed by the Performance Assurance Committee (PAC) and selected according to a set process.
We are being audited by MOSL, what can we expect?
We have produced an audit guidance document to support trading parties who are selected for an audit.
MOSL has also produced an Audit Suggestion Form that enables you to suggest future audits to the Market Assurance team. Your suggestion will be reviewed and added to the list of potential audits for the next financial year, according to the audit selection process.
2025-26
This audit focuses on wholesalers’ processes to identify and enter gap sites into the market.
| Document Name | Date Published | Author | File Download |
|---|---|---|---|
|
Problem Statement |
24 April 2025 |
MOSL |
Download |
This audit aims to review evidence supporting the submissions of B5, C1 and C5 requests to determine whether the requests were raised in the best interest of customers.
| Document Name | Date Published | Author | File Download |
|---|---|---|---|
|
Problem Statement |
24 April 2025 |
MOSL |
Download |
This audit focuses on whether requests completed within SLAs were resolved to the customer’s satisfaction.
| Document Name | Date Published | Author | File Download |
|---|---|---|---|
|
Problem Statement |
24 April 2025 |
MOSL |
Download |
This audit aims to establish the amount of consumption suppressed at R1 and RF due to low YVEs and the numbers of meters affected.
| Document Name | Date Published | Author | File Download |
|---|---|---|---|
|
Problem Statement |
24 April 2025 |
MOSL |
Download |
This audit focuses on assuring that deferrals are being applied in compliance with the market codes, and on providing insights into the use of deferrals across the market.
2017-2024
Here you will find all previous published documentation relating to earlier trading party audits
| Audit Name | Audit Description | Year of Audit | Author | Statement of Work | Initial Findings | Final Report |
|---|---|---|---|---|---|---|
|
Yearly Volume Estimates (YVEs) Settlement and Customer Impact |
This audit, delivered in collaboration with the Consumer Council for Water, focuses on the impact of YVEs, by analysing settlement data and copies of selected bills. |
2024-25 |
MOSL and CCW |
Published 25 July 2024 Download |
- |
Published 1 April 2025 Download |
|
Unplanned Settlement Runs (USRs) Review of causes |
This audit focuses on the data corrections that resulted in USRs and how to support timely and accurate settlement data. |
2024-25 |
MOSL |
Published 28 June 2024 Download |
- |
Published 31 January 2025 Download |
|
Wholesaler Tariffs Audit |
This audit focuses on assuring that tariff data uploaded in CMOS is appropriate and consistent with published tariffs. |
2024-25 |
MOSL |
Published 25 April 2024 Download |
- |
Published 26 September 2024 Download |
|
Skip Codes Audit |
This audit focuses on the skip codes used within the market and the processes surrounding their use |
2023-2024 |
MOSL |
Published 13 October 2023 Download |
- |
Published 25 April 2024 Download |
|
Yearly Volume Estimate (YVE) Audit |
This audit focuses on the processes surrounding the setting and maintenance of YVEs |
2023-2024 |
MOSL |
Published 19 July 2023 Download |
- |
Published 8 April 2024 Download |
|
Bilateral Deferrals Audit |
This audit focuses on wholesalers using the defer option within the Bilaterals hub and looks to assure the processes are being followed correctly |
2023-2024 |
MOSL |
Published 30 June 2023 Download |
Published 23 October 2023 Download |
Published 29 February 2024 Download |
|
Wholesaler Data Completeness Audit |
This audit focuses on meter and site data completeness between a wholesaler's own system and the data held in CMOS |
2023-2024 |
MOSL |
Published 1 July 2022 Download |
Published 24 February 2023 Download |
Published 12 October 2023 Download |
|
Non-Market Meter Performance Audit |
This audit focuses on wholesalers performing poorly against the Non-Market Meter performance tasks |
2022-2023 |
MOSL |
Published 16 January 2023 Download |
Published 24 January 2023 Download |
Published 26 April 2023 Download |
|
Transfer Behaviours Audit |
This audit focuses on the processes surrounding the transfer of customers |
2022-2023 |
MOSL |
Published 5 December 2022 Download |
Published 12 December 2022 Download |
Published 26 April 2023 Download |
|
Retailer Data Completeness Audit |
This audit focuses on meter reading and vacancy status completness between a retailer's own billing system and the data held in CMOS |
2022-2023 |
PwC and MOSL |
- |
Published 11 January 2023 Login to download |
Published 27 March 2023 Download |
|
Retailer Data Completeness Audit |
This audit focuses on meter reading and vacancy status completeness between a retailer's own billing system and the data held in CMOS |
2022-2023 |
PwC |
- |
Published 26 September 2022 Login to download |
- |
| Deferred payments review - Part 2 | This audit reviews key inputs of three Retailer’s October 2020 Deferred Payments submission | 2020-2021 | PwC |
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- |
Download |
| Deferred payments review - Part 1 | This audit reviews key inputs of three Retailer’s May, June and July 2020 Deferred Payments submission | 2020-2021 | PwC |
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- |
Download |
| COVID-19 Temporary Vacants | This audit covers the Assurance Statements submitted by five retailers, reviewing the processes followed by each retailer to identify those premises that they had marked as temporary vacant based on key criteria outlined in CPW091. | 2020-2021 | PwC |
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- |
Download |
| Vacants Review | This report covers a review of Vacants in the market, targeting the core 'SPID lifecycle' processes operating within companies, and bilaterally. Two wholesaler - retailer pairings were selected. | 2019-2020 | PwC |
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- |
Download |
| OPS Review Q2 | This audit focuses on three wholesalers and reviews their performance against the OPS of most significance to market operations, and the frequency of tasks performed. | 2019-2020 | PwC |
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- |
Download |
| OPS Review Q1 | This audit focuses on three wholesalers and reviews their performance against the OPS of most significance to market operations, and the frequency of tasks performed. | 2019-2020 | PwC |
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- |
Download |
| PwC 2019/20 Market Audit approach | This document outlines PwCs approach to the 2019/20 market audit | 2019-2020 | PwC |
Download |
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- |
| NHH Market Audit Report | This data led audit focuses on a variety of areas considered to be of higher risk to the market including, the meter reading processes, master data quality, switching, and CMOS configuration and alignment. | 2018-2019 | PwC |
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- |
Download |
| NHH Market Audit Report | This audit focuses on challenging the trading parties on their ability to comply with the WRC in higher risk areas, and identifying key areas of market improvement. | 2017-2018 | PwC |
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- |
Download |
Market Audit: Market Operator
Each year, external auditors test and report on MOSLs compliance to its obligations as set out within the Market Codes. These reports can be found below.
| Document Name | Year of Audit | Author | File Download |
|---|---|---|---|
| Review of MOSL Compliance | 2018-2019 | PwC | Download |
| Interim review of MOSL Compliance | 2019-2020 | PwC | Download |
| Review of MOSL Compliance | 2019-2020 | PwC | Download |
| Review of MOSL Compliance | 2020-2021 | PwC | Download |
| Review of MOSL Compliance | 2021-2022 | PwC | Download |
|
Review of MOSL Compliance |
2022-2023 |
PwC |
Download |
|
Review of MOSL Compliance |
2023-2024 |
PwC |
Download |
MOSL Audit: Quarterly Internal
MOSL provide quarterly reports to the Market Performance Committee (MPC) on how it is meeting its current obligations. These reports can be found below.
| Document Name | Quarter Reported | File Download |
|---|---|---|
|
Market Operator Compliance Report |
2024-2025 Q3 |
Download |
|
Market Operator Compliance Report |
2024-2025 Q2 |
Download |
|
Market Operator Compliance Report |
2024-2025 Q1 |
Download |
|
Market Operator Compliance Report |
2023-2024 Q4 |
Download |
|
Market Operator Compliance Report |
2023-2024 Q3 |
Download |
|
Market Operator Compliance Report |
2023-2024 Q2 |
Download |
|
Market Operator Compliance Report |
2023-2024 Q1 |
Download |
|
Market Operator Compliance Report |
2022-2023 Q4 |
Download |
|
Market Operator Compliance Report |
2022-2023 Q3 |
Download |
|
Market Operator Compliance Report |
2022-2023 Q2 |
Download |
|
Market Operator Compliance Report |
2022-2023 Q1 |
Download |
|
Market Operator Compliance Report |
2021-2022 Q4 |
Download |
| Market Operator Compliance Report | 2020-2021 Q3 | Download |
| Market Operator Compliance Report | 2020-2021 Q2 | Download |
| Market Operator Compliance Report | 2020-2021 Q1 | Download |
| Market Operator Compliance Report | 2019-2020 Q4 | Download |
| Market Operator Compliance Report | 2019-2020 Q3 | Download |
| Market Operator Compliance Report | 2019-2020 Q2 | Download |
| Market Operator Compliance Report | 2019-2020 Q1 | Download |
| Market Operator Compliance Report | 2018-2019 Q4 | Download |
| Market Operator Compliance Report | 2018-2019 Q3 | Download |
| Market Operator Compliance Report | 2018-2019 Q2 | Download |
| Market Operator Compliance Report | 2018-2019 Q1 | Download |
| Market Operator Compliance Report | 2017-2018 Q4 | Download |